using System;
public struct Ponto
{
	double x, y;
	public Ponto(double x, double y) { this.x = x; this.y = y; }
	public double distancia(Ponto P)
	{
		double d = (x-P.x) * (x-P.x) + (y-P.y) * (y-P.y);
		return Math.Sqrt(d);
	}
}

public class Teste
{
	public static void Main()
	{
		Ponto p1 = new Ponto();
		Ponto p2 = new Ponto(1, 1);
		Console.WriteLine(p2.distancia(p1));
	}
}